I think i may have piles i can feel the lump around the anus but only hurts when i pass?

Hemorrhoids: Sounds like you have an inflamed hemorrhoid. Straining with certain exercizes or bm's can make them worse. When they are painful, recommend drinking lots of water and changing diet to avoid constipation.

Probably right: Lumpy things around the anus that are painful and occasionally bleed at the end of stool in an 18 year old are probably just as you state. They should resolve with time. If they cause significant discomfort or are persistent you should seek care.